Prime Minister Prayut Chan-o-cha acknowledged on Tuesday there had been some delays in the government's mass Covid-19 vaccination campaign.

The campaign, which launched Monday, has been slowed by inadequate vaccine supply, but this would improve as more supplies were received, the PM said.

"I must apologise to anyone who experienced inconvenience," he said after a cabinet meeting at Government House."The government will try to acquire as many more vaccines as possible and not just wait for contracted vaccines, said Gen Prayut. "I believe that more vaccine doses will be delivered next month and services at inoculation stations in the provinces will be more conveniently managed.

"We do not want people who registered for vaccinations to suffer further delays."

The prime minister said the government aimed to eventually administer at least 100 million doses of Covid-19 vaccine to the Thai people.

It had signed contracts to buy 61 million doses of AstraZeneca's vaccine produced by Siam Bioscience and 6 million doses from Sinovac.

The government would also order eight million more doses from Sinovac, 25 million from Pfizer-BioNTech and Johnson & Johnson, and hoped to negotiate for extra supplies.

In addition, the government would start receiving a vaccine developed in Thailand, he said.

Mass vaccinations started on Monday, with more than 400,000 doses administered. The total number of vaccine recipients in the country now exceeded 4 million, Gen Prayut said.